Water Treatment Plant Startup

Issues and Considerations

Joe Guistino, Coastside County Water District

Aileen Kondo, Kennedy/Jenks Consultants

California-Nevada Section AWWA

Annual Fall Conference

2 October 2013

Sacramento, California

Presentation Overview

Project Background

DCWTP Improvements

Startup Issues and Operational Challenges

Current DCWTP Performance and Operations

Summary

Project Background

Nunes WTP

Water purchased

from SFPUC

Crystal Springs Reservoir

Pilarcitos Reservoir

Denniston Creek

WTP

Local surface water

Pilarcitos Well Field, -

ground water under the

influence of surface water

(Pilarcitos Creek)

Original DCWTP Treatment Process

Project Driver: Treat Used DC Water

Permit treating unused portion of Denniston

Creek water rights and reduce amount of

water purchase from City

High source water

tubidity (>15 NTU)

Unmanageable

backwash frequencies

Local water passed to

ocean unused

Project Driver: Upgrade of Old Facility

Upgrade aging facilities (original DCWTP

constructed in 1971)

• Unreliable high lift station

• Manual controls

• Aging chemical feel system

• No solids handling facility

Pipeline failure in 2010

Original DCWTP

Original High Lift Pumps

Original Flash Mixer

Aging Chemical Facilities

Alum Tank Permanganate Tank

Caustic Soda Pumps

Polymer SystemChemical Leak

Pipeline Failure

Project Objectives

Restore capacity to 1,000 gpm and enable realizing

up to 250 MG/year production

• Enable treating raw water turbidity up to 50 NTU

• Enable processing of spent washwater and larger volume

of solids

Improve water treatment plant operation and

reliability

• Upgrade high lift source water pumps

• Upgrade chemical storage and feed systems

• Provide automated controls

Upgraded DCWTP Treatment Process

Denniston Creek Pump Station

Pretreatment System

WWR and Solids Handling Facilities

Chemical Systems

Upgraded DCWTP

DCWTP Startup

400 gpm Test

700 gpm Test

2

1,000 gpm Test

30 31

17 18

1

24 2522 23

31

Raw Water Pump Startup

Raw water pump discharge

not reach plant at startup

Raw water was discharging

back into wet well due to

pressure relief valve setting

Check valve setting, in

addition to valve positions

before startup

Startup Testing Turbidity

Date Test

Alum

Dose

(mg/L)

Average Turbidity (NTU)

RW Coag. W Cl. W FW

1/22 400 gpm 17-27 5.4 9.6 4.3 0.06-0.10

1/23 700 gpm 20-26 6.2 9.8 7.3 0.06-0.09

1/24 700 gpm 19-26 6.5 10.9 5.9 0.05-0.07

1/25 700 gpm 6-10 5.6 8.8 3.7 0.42-0.53

1/31 1,000 gpm ~5 4.7 6.4 1.4 0.16-0.16

2/1 1,000 gpm ~5 5.5 - 1.0 0.05-0.06

Contact Clarifier Performance

Purpose of contact clarifiers is to reduce turbidity

ahead of filters

Applied coagulant dose of ~13-27 mg/L too high

clarified water turbidity (~4-7 NTU)

Reduced coagulant dose to ~5 mg/L significant

reduction in clarified water turbidity (~1-2 NTU)

With contact clarifiers, lower coagulant dose is

more effective for some operating conditions.

Startup Testing Turbidity

Date Test

Alum

Dose

(mg/L)

Average Turbidity (NTU)

RW Coag. W Cl. W FW

1/22 400 gpm 17-27 5.4 9.6 4.3 0.06-0.10

1/23 700 gpm 20-26 6.2 9.8 7.3 0.06-0.09

1/24 700 gpm 19-26 6.5 10.9 5.9 0.05-0.07

1/25 700 gpm 6-10 5.6 8.8 3.7 0.42-0.53

1/31 1,000 gpm ~5 4.7 6.4 1.4 0.16-0.16

2/1 1,000 gpm ~5 5.5 - 1.0 0.05-0.06

Oxidation Issues: Manganese

Observed black precipitate in chlorine analyzer

indication of manganese passing through filters

Yellow water complaints in the neighborhood

Measured manganese concentrations• Raw water manganese ~0.135 mg/L

• Treated water manganese ~0.165 mg/L

• Normal treated water manganese ~0.01-0.02 mg/L

Performed permanganate soak of greensand filters

and added potassium permanganate feed point

ahead of filters

Adsorbed manganese can release from filter media

if redox condition is not sustained.

Oxidation Issues: Iron

High iron levels observed in

raw water (1 mg/L)

Increased potassium

permanganate dose to

oxidized iron (0.5 mg/L

0.8 mg/L)

Observed floc formation in

jar test

Oxidizing ferrous iron (Fe+2) to ferric iron (Fe+3) provides “free”

(no cost) iron coagulation (1 mg Fe+3 = 3 mg FeCl3).

Washwater Recovery

Treatment objective is to reduce recycle water turbidity to less

than 2 NTU

Bulk of solids dropping off in WWR basin #1 with jet inlet

stream in circular basin

Great performance initially but not consistent

Controls System

Third party SCADA system

programmer

• Pros: Owner has greater control

over system controls; easier to

make future changes

• Cons: Additional level of

coordination

Contact clarifier system supplier

responsible for coagulant and

coagulant aid feed rate controls

Requiring pretreatment system

PLC to control chemical doses

can be restrictive.

Nice-to-haves Identified during Startup

Hose spigots for wash down in contact clarifier

area

Manual shutoff valves before automatic valves on

bulk chemical tanks

Additional chemical injection points and sample

ports

Algae removal ahead of contact clarifiers

Current DCWTP Operation and

Performance

Improved filter runs and reduced washwater generation with

contact clarifier pretreatment

Switched from Alum to PACl

• Longer filter runs

• Lower chemical use (replaces alum and cationic polymer)

• Less solids production

DCWTP temporarily shut down during summer due to current

low source water availability

Work on optimizing iron oxidation when DCWTP returns

online

Still yet to observe performance of contact clarifiers under

high source water turbidity conditions (raw water turbidity has

been between 5 - 10 NTU since startup)

Summary

Pressure contact clarifier pretreatment significantly

reduces coagulant use, improves filter runs, and reduces

generation of spent washwater in a small footprint

Add oxidant immediately ahead of greensand filters to

prevent desorption of manganese into filtered water

Oxidation of iron in raw water forms trivalent coagulant aid

If have proprietary control system for treatment process,

be sure to make arrangements to enable modifications if

needed

PACl greatly reduces chemical use and generation of

solids

Acknowledgments

Coastside County

Water District

David Dickson

Sean Donovan

Don Patterson

Matt Damrosch

John Davis

Kennedy/Jenks

Craig Thompson

Joel Faller

Joe Drago

Roberts Filter Group

Mike Gregg

Andre “Kumar” Razeek

Questions?

AileenKondo@KennedyJenks.com

JGuistino@CoastsideWater.org